In recent processes of manufacturing semiconductor devices, semiconductor devices are being further miniaturized, and the importance of pattern dimension management for such processes has increased. Patterns are formed to have three-dimensional structure, and thus, a manufacturing method of integrating the pattern has been applied. In order to manage the dimension of the pattern having the three-dimensional structure, it is necessary to evaluate performance of the pattern in a sectional direction. In order to evaluate the section of the pattern, a sample is cut and the section of the pattern seen on a fracture surface is observed. A method is considered, given a surface on which a section of the sample is exposed in a longitudinal direction, by drilling the sample in a direction perpendicular to the sample surface without cutting the sample and evaluating the section thereof.
Patent literature 1 (PTL 1) describes a method in which a sample thickness t is calculated by forming a taper-shaped inclined surface using a focused ion beam (FIB), acquiring a surface observed image of the formed inclined surface by using an electron microscope, and calculating 2·X·tan α based on an inclination angle α of the inclined surface.